Method and apparatus for treating acrylic fibers



R. VIRGIL March 28, 1961 METHOD AND APPARATUS FOR TREATING ACRYLICFIBERS Filed Jan. 29, 1958 INVENTOR.

RICHARD VIRGIL ATTORNEY METHOD AND APPARATUS FOR TREATING ACRYLIC FIBERSRichard Virgil, Flushing, N.Y., assignor to Templon Spinning Mills,Inc., Mooresville, N.C., a corporation Filed Jan. 29, 1958, Ser. No.712,007

7 Claims. (Cl. 19--'.37)

This invention relates to a method and apparatus for treating towcomposed of acrylic fibers. More specifically, the invention concernsthe thermal treatment of such tow in order to render the ultimate endproduct in the form of staple, much more uniform than heretofore inrespect to stretch or extensibility.

An object of this invention is to provide an improved method andapparatus for continuously treating tow made up of acrylic fibers suchas Orlon, acrilan or the like, wherein monofilaments move throughsuccessive sets of rollers running at differential speed in order tostretch the fibers, and further including heating means for heattreating the fibers in the tow to a predetermined elevated temperature.Furthermore, the tow is subjected to the action of breaker rolls afterthe same comes out of the heating means. In order to render the ultimateproduct more uniform as to extensibility, there is introduced a positivecooling means immediately after the heater means, whereby the heattreated tow is brought down to approximately room temperature veryrapidly and immediately before the same passes through the breakerrolls.

Heretofore, it has been known in the art to heat treat such continuousfilaments of acrylic fiber previous to passing the same through breakerrolls, in order to reduce the tow to staple. However, in such knownprocedures, it has been found that the ultimate yarns used in knittingor other textile operations were not uniform as to extensibility, suchas is encountered when the yarns or the fabric derived therefrom arefurther processed in order to produce simulated wool-like eft'ects. Withknown procedures it has been not uncommon to find that knitted materialsforming one portion of a garment would have greater dimension in a givendirection than an associated part of such knitted fabric.

The present invention is designed to reduce materially the relativelywide range of extensibilities in the finished staple so as to stabilizethe yarn for knitting or weaving operations.

in the drawing:

Fig. 1 is a diagrammatic representation of apparatus for treating towincluding monofilaments of acrylic fiber, in accordance with theinvention; and

Fig. 2 is an elevational view of the cooling roller which forms aportion of said apparatus.

Essentially, the method of this invention comprises passing the towwhich is made up of monofilament fibers or the acrylic type, such asOrlon or Acrilan through successive sets of rollers operating atdifferent speeds with an intervening heating plate which heats themoving fibers in the tow to temperatures of the order of 250 to 400 F.and stretches the same. Thereafter, the fibers are immediately passedover a cooling roller which is positively cooled by circulation of arefrigerating medium, such as cold or refrigerated water, the surfacetemperature of the roll being controlled in a manner to quickly bringthe temperature of the heat treated tow to approximately roomtemperature; that is between 75 2,976,5i Patented Mar. 23, 196i to 85 F.The tow, thereafter, then moves from feeding rolls through conventionalbreaker rolls to a final set of delivery rolls for tensioning thefilaments during the breaking operation. The thus stretched and treatedfibers in the tow are passed through a narrowing tray and stufiing boxin a manner conventional in the art.

It has been found that upon utilizing the staple fiber produced inaccordance with this invention, the admixture of fibers as received fromthe device herein to gether with other fibers, also derived from thisdevice, but which have been subjected to a relaxing procedure known inthe art, namely by subjecting selected portions of the treated tow to asteam bath, that such admixture of stretched and relaxed fibers willproduce a sliver which is quite uniform insofar as its ultimate stretchincident to further processing operations in connection with the weavingor knitting of the same.

As shown in Fig. 1, the apparatus embodying the instant inventionincludes successive guide rollers 110, 11, 12 and 15 through which passthe tow T made of monofilaments of acrylic fiber. The tow T also passesthrough crowned rollers 13 and 14, respectively located between guiderollers 11, 12 and 12, 15, whereby the filaments are spread into a fiatsliver.

The tow T then continues its movement through a set of adjustablepressure rollers 16 which may be adjustably spaced to provide a passageof proper thickness to pass the tow T on its way to a series of feedrollers 17, 18, 19 and 20. From roller 20, the tow passes through aheater 21 comprising an upper heater platen 22 and a lower heater platen23. Such platens may be electrically heated to raise the temperature ofthe moving tow to from 250 to about 400 F., in accordance with thespecific fiber being treated and its ultimate usage. The platens aremaintained at the selected temperatures by thermostatic control means,not shown. As the heated tow T leaves heater 21, it is passed todelivery rollers 24, 25, 26 and 27. The tow T passes to a set ofadjustable pressure rollers 32 which rotate at a speed greater than thatof rollers 16, thus stretching the tow to the extent desired, thestretch ranging from about 20 to about 80%.

I The heated tow T now passes about a hollow roller 28 which ispositively cooled, as by passing cold water therethrough. As shown inFig. 2, the roller 28 may be provided with cold water inlet 29 and anoutlet 30. A thermostatic control 31 on the inlet 29 is adapted tomaintain a proper surface temperature for the roller 23.

The roller 28 is kept at a temperature which will quickly cool theheated tow T to temperatures ranging from about to about 85 F. The coldor refrigerated water passing through roller 23 may be derived from asource not shown and may take the form of a continuous circulatorysystem.

The tow T now passes from feed rollers 32 and to a set of deliverypressure rollers 33 which rotate at a predetermined speed somewhatfaster than rollers lo and 32, to tension the tow T. Located betweenpressure rollers 32 and 33 is a set of breaker rollers 34 which compriseprojecting breaker blades 35. The rollers 34 are so arranged as to bringtheir breaker blades into meshing relation as indicated in the drawingand operative to deflect the moving tow T sharply or abruptly out of itspath. This action breaks the monofilaments into staple. The towcontaining the staple now passes from delivery rollers 33 to a narrowingtray 36 and is thereafter collected in a manner known in the art.

It has been found that acrylic monofilaments which have been heattreated at a temperature of about 265 F. and then rapidly cooled toabout F., using the above described apparatus, produce staple, whichupon subsequent processing and conversion into knitted or wovengarments, shows excellent uniformity of stretch. Apparently the quickcooling of the heated filaments exerts a stabilizing action on theultimateextensibility characteristics of the fiber.

Furthermore, it was found that the breaking action was more etficientwhen the tow has been treated in accordance with the instant invention.Thus the blades 35 produced a cleaner break and neps are substantiallyeliminated from the treated sliver.

It is understood that the several rollers shown are driven by means notshown, at speeds which will properly stretch the monofilaments whilebeing heat treated and will tension the same during the subsequentbreaking action.

As various changes might be made in the embodiment of the invention,without departing from the spirit thereof, it is understood that allmatter herein disclosed is by way of illustration and shall not bedeemed limiting except as set forth in the appended claims.

What is claimed is: V

1. The method of treating tow containing continuous monofilaments ofacrylic fiber comprising continuously advancing the tow longitudinally,continuously stretching the advancing tow while heating the tow to atemperature of from about 250 to about 400 F., rapidly cooling theheated tow to a temperature of from about 75 to about 85 F, andthereafter breaking the treated tow to form staple.

2. In the method of converting monofilaments of acrylic'fiber to staple,the steps of simultaneously stretching and heating the fibers to atemperature of from about 250 to about 400 F., immediately thereafterquickly cooling the stretched and heated fibers to a temperature of fromabout 75 to about 85 F and thereafter breaking the fibers to formstaple.

3. The method of converting tow containing continuous monofilaments ofacrylic fiber into staple comprising advancing said tow, heating theadvancing tow to a temperature of from 250 to 400 F., simultaneouslystretching the heated filaments, quickly cooling the heated tow to atemperature of from 75 to 85 F., tensioning the cooled tow andintermittently deflecting the tensioned tow abruptly out of its path ofmovement to progressively break the tensioned filaments at the point ofdeflection.

4. The method of converting tow containing continu-,

4 taneously stretching the heated filaments, passing the heatedstretched filaments through a cooling zone to rapidly reduce thetemperature of the heated filaments to "about F., tensioning the treatedfilaments, and breaking the tensioned filaments.

5. Apparatus for converting tow containing continuous monofilaments ofacrylic fiber into staple comprising means for advancing said tow, meansfor heating the advancing tow to a temperature of from about 250 toabout 400 F., means for stretching the advancing heated tow, means forrapidly cooling the heated tow to a tem perature of from 75 to F., meansfor tensioning the treated tow and means for breaking the tensioned tow.

6. Apparatus for converting tow containing continuous monofilaments ofacrylic fiber into staple comprising successive sets of rollers foradvancing and stretching the tow, means for heating the advancing towduring the stretching operation to at least about 250 F., means adjacentthe heating means for cooling the tow to a temperature of from about 75to 85 F., means for tensioning the cooled tow including spaced sets ofrollers operating at successively increased speeds, and means locatedbetween said spaced sets of rollers for intermittently deflecting thetow abruptly out of its path of movement to progressively break thetensioned filaments at the points of deflection.

7. Apparatus for converting continuous acrylic monofilaments into staplecomprising two successive sets of rollers for advancing said filamentsthrough a predetermined path, heater means located between said sets ofrollers for heating the advancing filaments to at least about 250 F.,cooling means located after the second set of rollers for rapidlyreducing the temperature of the heated filaments to from about 75 toabout 85 B, said sets of rollers operating at difierential speeds totension and extend the heated filaments, a third set of rollers forreceiving the advancing filaments from said cooling means, a fourth setof rollers operating at a speed higher than that of said third set ofrollers for tensioning the advancing filaments, and means between saidthird and fourth sets of rollers for sharply deflecting the advancingtensioned filaments to break said filaments to form staple fiber.

References Cited in the file of this patent UNITED STATES PATENTS2,096,795 Dreyfus Oct. 26, 1937 2,432,355 Truitt Dec. 9, 1947 2,649,623Ingham Aug. 25, 1953 2,748,426 Wyatt June 5, 1956 2,920,176 JorgensenJan. 5, 1960

2. IN THE METHOD OF CONVERTING MONOFILAMENTS OF ACRYLIC FIBER TO STAPLE,THE STEPS OF SIMULTANEOUSLY STRETCHING AND HEATING THE FIBERS TO ATEMPERATURE OF FROM ABOUT 250 TO ABOUT 400*F., IMMEDIATELY THEREAFTERQUICKLY COOLING THE STRETCHED AND HEATED FIBERS TO A TEMPERATURE OF FROMABOUT 75 TO ABOUT 85*F AND THEREAFTER BREAKING THE FIBERS TO FORMSTAPLE.